METHOD AND REACTOR FOR PRODUCING ONE OR MORE PRODUCTS
20230201790 · 2023-06-29
Inventors
- John Benjamin Hinkey, Jr. (Vancouver, CA)
- Timothy John Elder (Vancouver, CA)
- Kenneth William Kratschmar (Vancouver, CA)
- Christopher Edwin John Reid (Vancouver, CA)
Cpc classification
B01J19/24
PERFORMING OPERATIONS; TRANSPORTING
Y02E60/36
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
C01B2203/0827
CHEMISTRY; METALLURGY
H01M8/225
ELECTRICITY
C01B2203/043
CHEMISTRY; METALLURGY
B01J19/28
PERFORMING OPERATIONS; TRANSPORTING
B01J19/0013
PERFORMING OPERATIONS; TRANSPORTING
Y02E60/50
GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
H01M8/0618
ELECTRICITY
International classification
Abstract
A feedstock gas, such as natural gas, is introduced into a mixing chamber. A combustible gas is introduced into a combustion chamber, for example simultaneously to the introduction of the feedstock gas. Thereafter, the combustible gas is ignited so as to cause the combustible gas to flow into the mixing chamber via one or more fluid flow paths between the combustion chamber and the mixing chamber, and to mix with the feedstock gas. The mixing of the combustible gas with the feedstock gas causes one or more products to be produced.
Claims
1.-39. (canceled)
40. A method of decomposing a feedstock gas in a feedstock gas reactor, comprising: introducing the feedstock gas into a mixing chamber of the feedstock gas reactor; introducing a combustible gas into a combustion chamber of the feedstock gas reactor, wherein the combustion chamber is connected to the mixing chamber; combusting the combustible gas in the combustion chamber so as to form one or more combustion product gases, wherein the one or more combustion product gases flow into the mixing chamber and mix with the feedstock gas, and wherein, as a result of the mixing of the one or more combustion product gases with the feedstock gas, energy is transferred from the one or more combustion product gases to the feedstock gas and thereby causes a chemical reaction to decompose the feedstock gas and produce one or more reaction products; extracting a mixed product stream, comprising the one or more reaction products, from the mixing chamber; and recycling at least a portion of the mixed product stream to the feedstock gas reactor.
41. The method of claim 40, wherein: the mixed product stream comprises carbon; and the method further comprises separating at least some of the carbon from the mixed product stream.
42. The method of claim 40, wherein: the mixed product stream comprises hydrogen; and the method further comprises separating at least some of the hydrogen from the mixed product stream.
43. The method of claim 42, wherein separating the hydrogen comprises using pressure swing adsorption.
44. The method of claim 40, wherein: the mixed product stream comprises carbon and hydrogen; and recycling the at least a portion of the mixed product stream comprises: separating at least some of the carbon and at least some of the hydrogen from the mixed product stream to form a recycled gas mixture; and recycling the recycled gas mixture to the feedstock gas reactor.
45. The method of claim 44, wherein recycling the recycled gas mixture comprises: conditioning the recycled gas mixture to a desired temperature and pressure; and recycling the conditioned recycled gas mixture to the feedstock gas reactor.
46. The method of claim 44, wherein recycling the recycled gas mixture comprises: mixing a first fraction of the recycled gas mixture with an oxidant; mixing a second fraction of the recycled gas mixture with a source of the feedstock gas; and recycling the mixture of the oxidant and the first fraction of the recycled gas mixture, and the mixture of the feedstock gas and the second fraction of the recycled gas mixture, to the feedstock gas reactor.
47. The method of claim 46, wherein the first and second fractions sum to 1.
48. The method of claim 46, wherein recycling the mixtures comprises: introducing the mixture of the oxidant and the first fraction of the recycled gas mixture into the combustion chamber; and introducing the mixture of the feedstock gas and the second fraction of the recycled gas mixture into the mixing chamber.
49. The method of claim 48, wherein introducing the mixture of the oxidant and the first fraction of the recycled gas mixture into the combustion chamber comprises: conditioning the mixture of the oxidant and the first fraction of the recycled gas mixture to a desired temperature and pressure; and introducing the conditioned mixture into the combustion chamber.
50. The method of claim 48, wherein introducing the mixture of the feedstock gas and the second fraction of the recycled gas mixture into the mixing chamber comprises: conditioning the mixture of the feedstock gas and the second fraction of the recycled gas mixture to a desired temperature and pressure; and introducing the conditioned mixture into the mixing chamber.
51. The method of claim 40, wherein combusting the combustible gas comprises igniting the combustible gas.
52. The method of claim 40, wherein the feedstock is decomposed in a constant-volume reaction process.
53. A system comprising: feedstock gas reactor comprising: a mixing chamber; a combustion chamber connected to the mixing chamber; and at least one igniter; valving for controlling flow of gases into and out of the mixing chamber and the combustion chamber; and a controller operable to: control the valving to introduce a feedstock gas into the mixing chamber; control the valving to introduce a combustible gas into the combustion chamber; control the at least one igniter to combust the combustible gas in the combustion chamber so as to form one or more combustion product gases, wherein the one or more combustion product gases flow into the mixing chamber and mix with the feedstock gas, and wherein, as a result of the mixing of the one or more combustion product gases with the feedstock gas, energy is transferred from the one or more combustion product gases to the feedstock gas and thereby causes a chemical reaction to decompose the feedstock gas and produce one or more reaction products; control the valving to extract a mixed product stream, comprising the one or more reaction products, from the mixing chamber; and control the valving to recycle at least a portion of the mixed product stream to the feedstock gas reactor.
54. The system of claim 53, wherein: the mixed product stream comprises carbon and hydrogen; the system further comprises a carbon separator and a hydrogen separator for separating at least some of the carbon and at least some of the hydrogen from the mixed product stream to form a recycled gas mixture; and the controller is further operable to control the valving to recycle the recycled gas mixture to the feedstock gas reactor.
55. The system of claim 54, wherein the controller is further operable to control the valving to: mix a first fraction of the recycled gas mixture with an oxidant; mix a second fraction of the recycled gas mixture with a source of the feedstock gas; and recycle the mixture of the oxidant and the first fraction of the recycled gas mixture, and the mixture of the feedstock gas and the second fraction of the recycled gas mixture, to the feedstock gas reactor.
56. The system of claim 55, wherein the first and second fractions sum to 1.
57. The system of claim 55, wherein the controller is further operable to control the valving to: introduce the mixture of the oxidant and the first fraction of the recycled gas mixture into the combustion chamber; and introduce the mixture of the feedstock gas and the second fraction of the recycled gas mixture into the mixing chamber.
58. The system of claim 57, wherein: the system further comprises a combustion mixture conditioning and control system for conditioning the mixture of the oxidant and the first fraction of the recycled gas mixture to a desired temperature and pressure; and the controller is further operable to control the valving to introduce the conditioned mixture into the combustion chamber.
59. The system of claim 57, wherein: the system further comprises a feedstock mixture conditioning and control system for conditioning the mixture of the feedstock gas and the second fraction of the recycled gas mixture to a desired temperature and pressure; and the controller is further operable to control the valving to introduce the conditioned mixture into the mixing chamber.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] Embodiments of the disclosure will now be described in detail in conjunction with the accompanying drawings of which:
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DETAILED DESCRIPTION OF EMBODIMENTS
[0065] The present disclosure seeks to provide an improved method and reactor for producing one or more products. While various embodiments of the disclosure are described below, the disclosure is not limited to these embodiments, and variations of these embodiments may well fall within the scope of the disclosure which is to be limited only by the appended claims.
[0066] The word “a” or “an” when used in conjunction with the term “comprising” or “including” in the claims and/or the specification may mean “one”, but it is also consistent with the meaning of “one or more”, “at least one”, and “one or more than one” unless the content clearly dictates otherwise. Similarly, the word “another” may mean at least a second or more unless the content clearly dictates otherwise.
[0067] The terms “coupled”, “coupling” or “connected” as used herein can have several different meanings depending on the context in which these terms are used. For example, the terms coupled, coupling, or connected can have a mechanical or electrical connotation. For example, as used herein, the terms coupled, coupling, or connected can indicate that two elements or devices are directly connected to one another or connected to one another through one or more intermediate elements or devices via an electrical element, electrical signal or a mechanical element depending on the particular context. The term “and/or” herein when used in association with a list of items means any one or more of the items comprising that list.
[0068] As used herein, a reference to “about” or “approximately” a number or to being “substantially” equal to a number means being within +/−10% of that number.
[0069] Generally, according to embodiments of the disclosure, there is described an ultra-rich pulsed pyrolysis process used to produce hydrogen-rich gas and/or carbon products from natural gas feedstock. For large-scale hydrogen production, the process could compete with SMR.
[0070] According to embodiments of the disclosure, there is described the use of an unsteady, constant volume pulsed reaction process to produce hydrogen and carbon products from a natural gas-based feedstock. A separate chamber of combustible gases and an oxidant provides the energy for the reaction, and is transferred directly to the feedstock mixing chamber by gas-dynamic compression and rapid mixing thermal energy exchange via direct contact. In the discussion below, air is used as the oxidant; however, other oxidants such as pure oxygen can be used in the process. Furthermore, the feedstock gas and combustible gas can comprise the same gas or gas mixture or can comprise different gases or gas mixtures. In some embodiments, the combustible gas may comprise a recycled gas mixture.
[0071] The reactor comprises a mixing chamber and a combustion chamber. These chambers are connected via a number of passageways that are always open. In some embodiments, the reactor comprises a perforated tube (the combustion chamber) within a larger solid tube (the mixing chamber); see
[0072] Turning to
[0073] If the feedstock and combustible gases are premixed, the mixture may not ignite, as it is too rich. Therefore, the mixing chamber and combustion chamber are distinct and separate prior to ignition, such that no or preferably very little mixing occurs between the feedstock gas and the combustible gas.
[0074] A number of reactor systems may be bundled together and operated slightly out of phase with each other to produce a continuous flow into and out of the reactor system. Valves can be stationary or rotating, as shown in
[0075] Various parameters may be adjusted to enable the reactor to work effectively. The feedstock gas may be preheated to just below the temperature at which it starts to react, before being introduced into the mixing chamber. A typical temperature would be in the range of 600K-1000K, depending on the feedstock components and working pressures.
[0076] Furthermore, the combustible gas/oxidant mixture being introduced may also be preheated before entering the combustion chamber. A typical temperature would be in the range of 400K-700 K depending on the combustible gases used. Preheating the combustible gas/oxidant mixture may improve the efficiency of the process such that more combustion energy is transferred to the reactants rather than being used to heat the products of combustion.
[0077] The volume ratio between the mixing chamber and combustion chamber should be set such that the correct amount of energy contained in the combustion chamber is provided to the mixing chamber to produce the desired products. There should also be sufficient combustible gas products entering the mixing chamber to provide effective mixing. A volume ratio of <10:1 is generally desired. When using air as the oxidant, nitrogen may be beneficial as a non-reactive gas that promotes a lower volume ratio and increases mixing. When using pure oxygen as the oxidant, another gas such as CO.sub.2 may provide the same benefit as nitrogen in the air as oxidant case. Introducing additional CO.sub.2 to the combustible gas mixture may result in greater solid carbon production.
[0078] The length-to-diameter ratio is important to obtain efficient energy transfer from the combustion chamber to the mixing chamber. Short, large-diameter reactors will tend to have poor mixing while long, skinny reactors will develop challenges in introducing the feedstock and combustible gases into the reactor along its length. A length-diameter ratio of <30:1 is generally desired.
[0079] According to some embodiments, the reactor uses methane (or natural gas) in addition to some recycled product gases as the feedstock gas, and a recycled gas/oxidant mixture as the combustible gases. The reactor may be designed and operated to maximize the production of hydrogen and solid carbon in the reaction products stream. The reactor may comprise a combustion chamber, being a perforated tube, inside a mixing chamber. The perforated combustion chamber may be offset from the center of the mixing chamber and bonded to a wall of the mixing chamber to provide structural integrity and support, as can be seen in
[0080] As can be seen in
[0081] The reactor may be operated at a sufficiently high pressure such that the resulting hydrogen can be purified using standard pressure swing absorption technology. According to some embodiments, product gases such as unreacted methane (CH.sub.4), carbon monoxide (CO) and some hydrogen are recycled and mixed with more methane to produce the feedstock gas mixture to the reactor. The combustible gas mixture comprises the recycled gas mixture in addition (in the case of an air-blown reactor) to the CO.sub.2 removed from the CO.sub.2 removal system, and pure oxygen. In some embodiments, the recycled gas mixture flowing to both the combustion and mixing chambers contains CO.sub.2 in addition to CH.sub.4, CO and H.sub.2. The feedstock gas mixture and the combustible gas mixture are preheated to ˜900K and ˜600K respectively, from thermal energy recovered from the reactor products stream via a multi-stream heat exchanger. In alternative embodiments, the mixing chamber/combustion chamber volume ratio is 3.5:1, methane (or natural gas)/air mixture is used for the combustible gases.
[0082] There will now be provided a detailed description of embodiments of the disclosure.
[0083] With reference to
[0084] Chamber 60 is a constant volume device which uses the combustion energy from the conditioned combustible gas mixture 31 to increase the pressure and temperature of the conditioned feedstock mixture 51 to a reaction ready level. A combustion product gas mixture 67 comprising mainly of the combustion products of combusted conditioned combustible gas mixture 31 may be vented from chamber 60. The reaction ready gas mixture 61 enters the reactor 70, whereby it remains until the gas mixture is converted in a constant volume endothermic reaction to the reacted product mixture 71. The constant volume reaction is an unsteady process which operates in a batch mode and requires control of flow timing. This is accomplished by flow control in conditioning systems 30, 50, and separation and control system 80.
[0085] The reacted product mixture 71 enters the product separation and control system 80 which stops the reaction in reactor 70 by reducing the pressure and temperature of the desired reacted product mixture 71 and separates and/or purifies the individual product components 81, 82, the unwanted products 83 and the recycle gas mixture 84. The recycle gas mixture 84 enters the pre-conditioning recycle gas system 90 where the recycle gas mixture 84 is pre-conditioned to the desired temperature and pressure and flows to the feedstock mixture conditioning and control system 50.
[0086] In some embodiments, the combustible gas 10 and the feedstock gas 40 are natural gas, and the oxidant gas 20 is air. The desired reaction in reactor 70 is methane pyrolysis generally given by the following equation:
CH.sub.4 (methane)+energy.fwdarw.C (carbon)+2H.sub.2 (hydrogen)
[0087] The individual product 81 is hydrogen gas, the individual product 82 is carbon, and the unwanted products 83 are primarily carbon dioxide, nitrogen and water. The recycle gas mixture 84 comprises primarily of unreacted natural gas, hydrogen, nitrogen and carbon monoxide.
[0088] The system in
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[0091] Constant volume reactor 62 comprises a combustion volume 65 contained within combustion chamber 63. Combustion chamber 63 is surrounded by reactor volume 64 which is contained in reactor chamber 68. Passageways 66 connect combustion volume 65 to reactor volume 64. Although combustion chamber 63 is shown in the center of reactor chamber 68, the combustion chamber 63 can be located anywhere in reactor chamber 68, including against the outside wall 69 of the reactor chamber 68.
[0092] Conditioned combustible gas mixture 31 enters combustion chamber 63 through combustible gas mixture valve 32 and passageway 33, displacing any combustion product gas mixture 67 present in combustion volume 65 out of reactor 62 via passageway 74 and combustion product valve 75. Conditioned feedstock gas mixture 51 enters mixing chamber 68 through feedstock gas mixture valve 52 and passageway 53, displacing desired reacted product mixture 71 in reactor volume 64 out of reactor 62 via passageway 73 and product valve 72. Both the conditioned combustible gas mixture 31 and the conditioned feedstock gas mixture 51 may simultaneously enter constant volume reactor 62 at the same pressure such that there is very little mixing via passageways 66.
[0093] Once predominantly all the combustible gas mixture 67 and desired product mixture 71 is displaced from reactor 62, combustion product valve 75 and product valve 72 are closed. Once the desired reactor pressure is reached, combustible gas mixture valve 32 and feedstock gas mixture valve 52 are closed, creating a closed volume in reactor 62. Igniter 100 creates ignition energy 101 which allows conditioned combustible gas mixture 31 in combustion chamber 63 to combust in an exothermic reaction creating combustion product gas mixture 67 at elevated temperature and pressure. Due to the resulting pressure difference between combustion chamber 63 and mixing chamber 68, a portion of combustible gas mixture 67 enters reactor volume 64, compressing feedstock gas mixture 51 to a higher pressure. Simultaneously, this portion of hot combustible gas mixture 67 mixes and heats feedstock gas mixture 51 by conduction, convection and radiation. Feedstock gas mixture 51 is now at an elevated temperature and pressure which creates the conditions for an endothermic reaction to occur. Constant volume reactor 62 is maintained as a closed volume until the endothermic reaction proceeds long enough to create desired product mixture 71. Once this condition is reached, product valve 72 and combustion product valve 75 are opened which drops the pressure and temperature, stopping the endothermic reaction. The process then repeats.
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[0096] In order to create a quasi or semi-continuous flow system, multiple chambers 60 or constant volume reactors 62 can be arranged together and operated out of phase such that each chamber or reactor is undergoing a different part of the process described in
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[0098] Combustion product gas mixtures 67 from each constant volume reactor 62 is collected in combustion product plenum 123 and distributed out of the multitube reactor 110 via passageway 125. Product mixture 71 from each constant volume reactor 62, is collected in product plenum 124 and distributed out of the multitube reactor 110 via passageway, 126.
[0099] While the disclosure has been presented primarily in the context of the cracking of a feedstock gas, the disclosure extends to other methods of producing one or more products from a feedstock gas. For example, syngas (H.sub.2 and CO) may be produced by adjusting one or more parameters of the process such that the combustible gas reacts (in addition to mixing) with the feedstock gas. For instance, the ratio of oxidant to recycled gas in the combustible gas may be increased, to increase the pressure and temperature of the combustible gas immediately after ignition, and thereby induce an appropriate reaction between the combustible gas and the feedstock gas.
[0100] While the disclosure has been described in connection with specific embodiments, it is to be understood that the disclosure is not limited to these embodiments, and that alterations, modifications, and variations of these embodiments may be carried out by the skilled person without departing from the scope of the disclosure. It is furthermore contemplated that any part of any aspect or embodiment discussed in this specification can be implemented or combined with any part of any other aspect or embodiment discussed in this specification.